This invention is generally directed to toner and developer compositions, and more specifically, the present invention is directed to developer and toner compositions containing novel polyimide resins, and process for the preparation thereof. In embodiments, there are provided in accordance with the present invention, low cost, and rapid jetting toner compositions comprised of certain economical polyimide amine resins obtained, for example, by melt condensation processes, and pigment particles comprised of, for example, carbon black, magnetites, or mixtures thereof, cyan, magenta, yellow, blue, green, red, or brown components, or mixtures thereof thereby providing for the development and generation of black and/or colored images. In embodiments, there are provided in accordance with the present invention polyimide resins of the following formula ##STR2## wherein n represents the number of repeating segments and can be a number of from about 10 to about 1,000; and R is an aliphatic component such as alkyl, oxyalkyl or polyoxyalkyl. The toner compositions of the present invention in embodiments possess a number of advantages including low materials cost, such as from about $0.75 to about $1.00 per pound as, for example, estimated from the Chemical Marketing Reporter (1993 issue), low fixing characteristics such as from about 125.degree. C. to about 145.degree. C., excellent blocking characteristics such as from about 55.degree. C. to about 65.degree. C., rapid jetting characteristics such as rates of from about 0.90 to about 2.2 relative, for example, to poly(propoxylated bisphenol A-fumarate) resin, excellent nonvinyl-offset properties, and low relative humidity sensitivities. The polyimides of the present invention can in embodiments be generated by the reaction of ethylene diamine tetracarboxylic acid, and a diamino terminated oxyalkyl or polyoxy alkyl, such as JEFFAMINES.TM. available from Texaco Chemicals as JEFFAMINE D-230.TM., D-400.TM., D-700.TM., EDR-148.TM., EDR-192.TM. and believed to be of the following formula, or aliphatic diamines, like DYTEK.TM..
______________________________________ ##STR3## wherein ______________________________________ EDR-148 n = 2; R = H EDR-192 n = 3; R = H D-230 n = 2 or 3; R = CH.sub.3 D-400 n = 5 or 6; R = CH.sub.3 ______________________________________
The aforementioned polyimides exhibit in embodiments a number average molecular weight of from about 2,500 grams per mole to about 100,000 grams per mole as measured by vapor phase osmometry, have a glass transition temperature of from about 45.degree. C. to about 65.degree. C., and more preferably of from about 50.degree. C. to about 65.degree. C. as measured by the Differential Scanning Calorimeter, low fixing characteristics, such as from about 125.degree. C. to about 145.degree. C., and rapid jetting characteristics, such as rates of from about 0.90 to about 2.2 relative to poly(propoxylated bisphenol A) toner resins, and a M.sub.w of from about 1,500 to about 20,000.
In reprographic technologies, such as xerographic and ionographic devices, toners with small average volume diameter particle sizes of from about 11 microns to about 20 microns are usually utilized. Moreover, in some xerographic technologies, such as the high volume Xerox Corporation 5090 printers, high resolution characteristics and low image noise are highly desired, and can be attained utilizing small sized toners with average volume particle of less than 11 microns and preferably less than about 7 microns, and with a narrow geometric size distribution of less than about 1.4 and preferably of about 1.3 reported as the square root of the 84 percent volume particle size divided by the 15 percent volume particle size. Numerous processes are known for the preparation of toners, such as for example conventional processes wherein a resin is melt kneaded or extruded with a pigment, micronized and pulverized to provide toner particles with an average volume particle diameter of from about 7 microns to about 20 microns, and with geometric size distribution of from about 1.4 to about 1.7, followed by classification such that the geometric size distribution is reduced to from about 1.3 to about 1.42. Numerous pulverization processes are also known to reduce the particle size of toners to under 11 microns and preferably from 3 to 7 microns in average volume diameter. During the pulverization of jetted toners to less than about 11 microns, the geometric size distribution attained is from about 1.4 to about 1.7, and classification methods must be utilized to reduce the geometric distribution to less than 1.4. During classification processes, the amount of toner fines discarded is from about 30 to about 55 percent by weight of toner. To avoid or minimize the loss of toner fines, it is necessary to utilize toners comprised of base resins wherein rapid jetting can be selected. Rapid jetting can be quantified by relating toner resin jetting rates. One resin chosen for such quantification comparison is poly(propoxylated bisphenol A) with an average molecular weight of from about 10,000 to about 12,000 as measured by gel permeation chromatography and with a glass transition temperature of from about 53.degree. C. to about 55.degree. C. as measured by differential scanning calorimetry. It has been observed that in certain situations poly(propoxylated bisphenol A-fumarate) resin can be pulverized to about 5 microns in average volume diameter size with a low loss of resin fines, such as less than about 15 percent by weight or, more specifically, about 10 percent after classification. The relative jetting rate of a resin, such as the polyimide of the present invention (A), can then be measured by pulverizing it to a specified average volume diameter size, such as about 5 microns, by controlling the feed rate of the resin into the pulverizing chamber. This feeding rate is then compared to the feed rate utilized in pulverizing the poly(propoxylated bisphenol A-fumarate) resin (B) to the same specified average volume diameter size such as about 5 microns. The relative jetting rate of a resin (A) is then given by the ratio of the feed rates;
R.R.=Feed rate of (A), Feed rate of (B) PA1 R.R. is the relative jetting rate of the resin (A); PA1 (A) is the resin to be measured; PA1 (B) is comparative resin poly(propoxylated bisphenol A).
wherein,
It is observed that resins with a relative jetting rate of 0.75 or below are usually considered to be slow jetting, and results in high loss of fines such as from about 35 percent to about 55 percent by weight when pulverized to about 7 microns in volume average diameter. Resins with relative jetting rates of 1.0 are considered as acceptable jetting resins, and result in low loss of fines, such as from about 10 percent to about 15 percent by weight when pulverized to about 7 microns. Resins with rapid relative jetting rates of 2.0 or higher are considered to be excellent, and result in low loss of fines, such as about 9 percent by weight when pulverized to about 7 microns.
A number of toner resins are known, such as styrene acrylates, styrene methacrylates, styrene butadiene, polyesters, polyamides, and the like.
Certain polyimide resins and, more specifically, liquid crystalline polyimide resins are known such as summarized and illustrated in the Encyclopedia of Polymer Science and Engineering, 2nd Edition, Volume No. 12, published by Wiley (1985). However, such polyimide resins are aromatic and useful as high performance materials, there being no disclosure for use as toners.
Thermotropic liquid crystalline polyimides are illustrated in U.S. Pat. No. 5,348,930, filed concurrently herewith, the disclosure of which is wholly incorporated herein by reference, which discloses toner and developer compositions with thermotropic liquid crystalline polyimides. The polyimide resins of this invention differ in that, for example, they do not exhibit liquid crystalline properties, and moreover are of substantially lower cost such as from about 80 percent to about 500 percent less than the liquid crystalline polyimides of U.S. Pat. No. 5,348,930 as estimated, for example, from the Chemical Marketing Reporter (1993 issue). Also, the imide structures of the resins of the present invention are comprised of a cyclic six membered ring containing a tertiary alkyl amine as contrasted to the aforementioned liquid crystalline polyimides of U.S. Pat. No. 3,348,930, wherein the imide structure is comprised of a five membered cyclic ring without a tertiary alkyl amine moiety.
Illustrated in the following copending applications, the disclosures of each being totally incorporated herein by reference, are:
U.S. Ser. No. 144,075, filed concurrently herewith, illustrates a toner composition comprised of a pigment and a crosslinked polyimide; and wherein the crosslinked polyimide can be obtained from the reaction of a peroxide with an unsaturated polyimide of the formula ##STR4## R is alkyl or oxyalkylene and m represents the number of monomer segments present and is a number of from about 10 to about about 1,000.
U.S. Pat. No. 5,348,831, illustrates a toner composition comprised of pigment, and a polyester imide resin of the formula ##STR5## wherein n represent the number of segments present and is a number of from about 10 to about 10,000; R' is alkyl or alkylene; and R is independently selected from the group consisting of an oxyalkylene and polyoxyalkylene.
U.S. Ser. No. 144,918, filed concurrently herewith, illustrates a toner composition comprised of pigment, and polyimide of the formula ##STR6## wherein m, represent the number of monomer segments present; X is ##STR7## thus X can be benzophenone, oxydiphthalic, hexafluoropropane diphenyl, diphenyl sulfone, or biphenyl; and X is attached to four imide carbonyl moieties; and R is independently selected from the group consisting of alkyl, oxyalkylene and polyoxyalkylene.